Many expensive electronic components are packed in containers, such as trays, in which multiple discrete components are arranged in a matrix on each tray. The trays are designed so that multiple trays can be stacked together to increase the number of components positioned in one place, such as for transport or on a pick-and-place board assembly machine. During transport, each stack of trays is tied together with strapping material and packaged inside Electro-Static Discharge (ESD) bags. Typically, each stack of trays carries components of the same part number and lot code, with the part number and lot code information printed on a label attached to the outside of the bag.
Electrical components are usually placed onto printed circuit boards by a component placement machine. The most common configuration for components provided on trays is a tray tower on the placement machine. Trays of different part numbers are placed onto different ‘movable’ drawers inside the tray tower. At least one tray of components can be placed into each drawer. Sometimes, a stack of trays can be placed onto one drawer and the placement machine can remove the tray on the top of the stack after all the components on the top tray are consumed. The placement machine selects different part numbers by moving the entire drawer assembly up and down, or otherwise positioning the pick head with respect to a desired drawer. The drawer with the desired part number is then pulled out from the tray tower for picking. In many machines, the dispensing of components is always at the same level since the pick up mechanism of the placement machine is configured to always pick up components at the same vertical position.
Depending on various parameters, a particular electrical component may be more or less sensitive to being damaged during exposure to reflow soldering conditions based on exposure to moisture. The term “reflow soldering conditions” refers generally to the environmental conditions associated with a process of securing electrical components to a circuit board, substrate or other supporting structure. In a typically reflow soldering process, the electrical components may be exposed to an elevated temperature for some period of time. Dry storage containers may be provided to store electrical components over an extended period of time. However, an electrical component may be exposed to varying levels of ambient moisture prior to being reflow soldered to an electrical assembly.
Electrical components may be supplied in containers other than trays.